--- title: "Modulating Heart Activity and Task Performance using Haptic Heartbeat Feedback: A Study Across Four Body Placements" authors: - Andreia Valente - Dajin Lee - Seungmoon Choi - Mark Billinghurst - Augusto Esteves year: 2024 venue: "ACM Symposium on User Interface Software and Technology (UIST 2024)" doi: "10.1145/3654777.3676435" url: "https://andreia-valente.com/publications/valente2024modulating.html" pdf: "https://andreia-valente.com/pdfs/valente2024modulating.pdf" topics: - Haptics - Heartbeat Feedback - Physiological Computing - Interoception - Wearable Haptics --- # Modulating Heart Activity and Task Performance using Haptic Heartbeat Feedback: A Study Across Four Body Placements ## Citation Metadata - Authors: Andreia Valente, Dajin Lee, Seungmoon Choi, Mark Billinghurst, Augusto Esteves - Venue: ACM UIST 2024 - Year: 2024 - DOI: https://doi.org/10.1145/3654777.3676435 - HTML: https://andreia-valente.com/publications/valente2024modulating.html - PDF: https://andreia-valente.com/pdfs/valente2024modulating.pdf ## Plain-Language Summary This paper investigates whether simulated heartbeat haptics can influence actual cardiac activity and task performance, and whether those effects depend on where the haptic feedback is placed on the body. Participants received vibrotactile heartbeat feedback at the chest, wrist, neck, and ankle, using two heartbeat rates: 50 bpm and 110 bpm. The study measured heart rate, heart rate variability, task behavior, and subjective experience. The central result is that body placement matters. The wrist, despite being the default location for many wearable devices, was not the strongest site for modulating cardiac activity. Neck placement produced higher heart rates and lower heart rate variability, while ankle placement paired with faster feedback also increased heart rate. Chest placement was preferred subjectively and was associated with more comfortable experience ratings. ## Method The study used a wearable haptic system that delivered heartbeat-like vibrotactile pulses to four body locations. Participants experienced conditions with different placement and feedback rate while performing a cognitive task. The experiment compared physiological measures, performance measures, and self-reported experience across placements and rates. The design tests a core question in physiological computing: whether external body-like signals can influence internal bodily state, and whether the body site of stimulation changes the strength and quality of that influence. ## Key Findings - Neck placement produced higher heart rate and lower heart rate variability compared with several other conditions. - Faster haptic heartbeat feedback tended to increase heart rate and reduce heart rate variability. - Ankle stimulation at 110 bpm was especially effective at increasing heart rate. - Wrist stimulation was relatively weak despite the popularity of wrist-worn devices. - Chest feedback was preferred and produced better subjective experience ratings. - Physiological potency and user comfort are not the same design goal; the most effective stimulation can also be less pleasant. ## Design Implications Designers should choose haptic placement based on the desired physiological and experiential effect. Chest placement is appropriate when comfort, plausibility, and user acceptance matter. Neck placement can be physiologically powerful but may be distracting or uncomfortable. Ankle placement offers a less obvious site that can still influence cardiac activity, especially with faster rhythms. Wrist placement should not be assumed to be optimal simply because it is familiar. ## Detailed Findings by Placement The study compared vibrotactile heartbeat feedback at the chest, wrist, neck, and ankle using low-frequency and high-frequency heartbeat rhythms. The work treats haptic heartbeat feedback as an interoceptive design material: a simulated bodily signal that can alter how users attend to, interpret, and regulate their own physiological state. Neck placement produced the strongest stress-like physiological profile, with higher heart rate and lower heart rate variability. High-frequency feedback further increased heart rate and reduced heart rate variability, making neck stimulation a powerful but potentially uncomfortable choice. The paper therefore recommends avoiding neck placement when the goal is subtle or subconscious feedback. Ankle stimulation was less salient to users but could still affect heart activity, especially under high-frequency feedback. This makes the ankle useful when designers want a less attention-demanding site for physiological modulation. Chest placement produced more favorable subjective experience, including lower anxiety and higher heart rate variability than several other placements, and users perceived it as more congruent with the real heartbeat. The study also found that high-frequency haptic heartbeat feedback reduced answer time in the task, while low-frequency feedback increased self-reported autotelic experience, harmony, and perceived congruence between the haptic signal and the user's own heartbeat. Participants with lower interoceptive accuracy tended to experience more anxiety from haptic feedback, suggesting that bodily self-awareness can moderate the effect of these interfaces. ## Limitations and Future Work The authors note that the baseline lacked the Velcro strap used during stimulation conditions, so future work should better control for tactile pressure independent of vibrotactile feedback. Each trial lasted only one minute, making the findings most relevant to immediate physiological response rather than long-term adaptation. The task context was also narrow, so additional work should test social, emotional, and sustained-use settings. Future applications include simulated heartbeat feedback for emotional regulation, stress modulation, social interaction, emotional contagion, empathy, and collaboration. The paper is especially relevant to designers who want to select haptic placement based on whether they value comfort, salience, physiological effect, or unobtrusive background feedback. ## Why This Paper Matters This work is relevant for haptic biofeedback, affective computing, interoceptive interfaces, stress modulation, and wearable design. It provides empirical evidence that body placement is a meaningful design variable in heartbeat-like feedback systems. ## Recommended Citation Valente, A., Lee, D., Choi, S., Billinghurst, M., & Esteves, A. (2024). Modulating heart activity and task performance using haptic heartbeat feedback: A study across four body placements. In Proceedings of the 37th Annual ACM Symposium on User Interface Software and Technology. Association for Computing Machinery. https://doi.org/10.1145/3654777.3676435 ```bibtex @inproceedings{valente2024modulating, author = {Valente, Andreia and Lee, Dajin and Choi, Seungmoon and Billinghurst, Mark and Esteves, Augusto}, title = {Modulating Heart Activity and Task Performance Using Haptic Heartbeat Feedback: A Study Across Four Body Placements}, year = {2024}, booktitle = {Proceedings of the 37th Annual ACM Symposium on User Interface Software and Technology}, publisher = {Association for Computing Machinery}, doi = {10.1145/3654777.3676435}, url = {https://doi.org/10.1145/3654777.3676435} } ```